/******************************************************************************
* The MIT License
* Copyright (c) 2003 Novell Inc.  www.novell.com
* 
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* of this software and associated documentation files (the Software), to deal
* in the Software without restriction, including  without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
* copies of the Software, and to  permit persons to whom the Software is 
* furnished to do so, subject to the following conditions:
* 
* The above copyright notice and this permission notice shall be included in 
* all copies or substantial portions of the Software.
* 
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*******************************************************************************/
//
// Novell.Directory.Ldap.Controls.LdapVirtualListResponse.cs
//
// Author:
//   Sunil Kumar (Sunilk@novell.com)
//
// (C) 2003 Novell, Inc (http://www.novell.com)
//

using System;
using System.IO;
using Novell.Directory.Ldap.Asn1;

namespace Novell.Directory.Ldap.Controls
{
    /// <summary>
    ///     LdapVirtualListResponse is a Server Control returned by the server in
    ///     response to a virtual list search request.
    /// </summary>
    /// <summary>
    ///     In response to a VLV Search request the server returns an error code
    ///     and if the search was successful returns the following information:
    ///     <li> an index into the search results from where the returned list begins</li>
    ///     <li> an estimate of the total number of elements in the search result</li>
    ///     <li>
    ///         an optional context field to be returned to the server with
    ///         subsequent VLV request.
    ///     </li>
    /// </summary>
    public class LdapVirtualListResponse : LdapControl
    {
        /// <summary>
        ///     Returns the size of the virtual search results list.  This integer as
        ///     the servers current estimate of what the search result size.
        /// </summary>
        public virtual int ContentCount
        {
            get { return m_ContentCount; }
        }

        /// <summary>
        ///     Returns the index of the first entry in the returned list.  The server uses
        ///     the clients request information in conjunction with its current search result
        ///     list to estimate what list of entries the client is requesting.  This integer
        ///     is the index into the search results that is returned to the client.
        /// </summary>
        public virtual int FirstPosition
        {
            get { return m_firstPosition; }
        }

        /// <summary> Returns the result code for the virtual list search request.</summary>
        public virtual int ResultCode
        {
            get { return m_resultCode; }
        }

        /// <summary>
        ///     Returns the cookie used by some servers to optimize the processing of
        ///     virtual list requests. Subsequent VLV requests to the same server
        ///     should return this String to the server.
        /// </summary>
        public virtual string Context
        {
            get { return m_context; }
        }

        /* The parsed fields are stored in these private variables */
        private readonly int m_firstPosition;
        private readonly int m_ContentCount;
        private readonly int m_resultCode;

        /* The context field if one was returned by the server */
        private readonly string m_context;

        /// <summary>
        ///     This constructor is usually called by the SDK to instantiate an
        ///     a LdapControl corresponding to the Server response to a Ldap
        ///     VLV Control request.  Application programmers should not have
        ///     any reason to call the constructor.  This constructor besides
        ///     constructing a LdapVirtualListResponse control object also
        ///     parses the contents of the response into local variables.
        ///     RFC 2891 defines this response control as follows:
        ///     The controlValue is an OCTET STRING, whose value is the BER
        ///     encoding of a value of the following ASN.1:
        ///     VirtualListViewResponse ::= SEQUENCE {
        ///     targetPosition    INTEGER (0 .. maxInt),
        ///     contentCount     INTEGER (0 .. maxInt),
        ///     virtualListViewResult ENUMERATED {
        ///     success (0),
        ///     operationsError (1),
        ///     unwillingToPerform (53),
        ///     insufficientAccessRights (50),
        ///     busy (51),
        ///     timeLimitExceeded (3),
        ///     adminLimitExceeded (11),
        ///     sortControlMissing (60),
        ///     offsetRangeError (61),
        ///     other (80) },
        ///     contextID     OCTET STRING OPTIONAL }
        /// </summary>
        /// <param name="oid">
        ///     The OID of the control, as a dotted string.
        /// </param>
        /// <param name="critical">
        ///     True if the Ldap operation should be discarded if
        ///     the control is not supported. False if
        ///     the operation can be processed without the control.
        /// </param>
        /// <param name="values">
        ///     The control-specific data.
        /// </param>
        [CLSCompliant(false)]
        public LdapVirtualListResponse(string oid, bool critical, sbyte[] values) : base(oid, critical, values)
        {
            /* Create a decoder object */
            var decoder = new LBERDecoder();
            if (decoder == null)
                throw new IOException("Decoding error");

            /* We should get back an ASN.1 Sequence object */
            var asnObj = decoder.decode(values);
            if (asnObj == null || !(asnObj is Asn1Sequence))
                throw new IOException("Decoding error");

            /* Else we got back a ASN.1 sequence - print it if running debug code */

            /* Get the 1st element which should be an integer containing the
            * targetPosition (firstPosition)
            */
            var asn1firstPosition = ((Asn1Sequence) asnObj).get_Renamed(0);
            if (asn1firstPosition != null && asn1firstPosition is Asn1Integer)
                m_firstPosition = ((Asn1Integer) asn1firstPosition).intValue();
            else
                throw new IOException("Decoding error");

            /* Get the 2nd element which should be an integer containing the
            * current estimate of the contentCount
            */
            var asn1ContentCount = ((Asn1Sequence) asnObj).get_Renamed(1);
            if (asn1ContentCount != null && asn1ContentCount is Asn1Integer)
                m_ContentCount = ((Asn1Integer) asn1ContentCount).intValue();
            else
                throw new IOException("Decoding error");

            /* The 3rd element is an enum containing the errorcode */
            var asn1Enum = ((Asn1Sequence) asnObj).get_Renamed(2);
            if (asn1Enum != null && asn1Enum is Asn1Enumerated)
                m_resultCode = ((Asn1Enumerated) asn1Enum).intValue();
            else
                throw new IOException("Decoding error");

            /* Optional 4th element could be the context string that the server
            * wants the client to send back with each subsequent VLV request
            */
            if (((Asn1Sequence) asnObj).size() > 3)
            {
                var asn1String = ((Asn1Sequence) asnObj).get_Renamed(3);
                if (asn1String != null && asn1String is Asn1OctetString)
                    m_context = ((Asn1OctetString) asn1String).stringValue();
            }
        }
    }
}